Multicolor electronic devices and processes of forming the same by printing

ABSTRACT

There is provided a process of forming a regular array of rows of subpixels on a workpiece. The subpixels having 3 different colors, and a subpixel pitch s. Of the three colors, q colors are formed by printing and r colors are formed by a non-printing method. The process includes the steps: (1) providing a printing head having z nozzles arranged in a row with a spacing between the nozzles of p, where z=3n 1  and p=2s, the printhead being at a first position relative to the workpiece; (2) providing q different printing inks, one for each of the q printed colors; (3) supplying each of the printing inks to the nozzles in a regular alternating pattern; (4) printing a first set of z rows of subpixels with the printing head; (5) moving and printing in a first pattern with the steps: (a) moving the workpiece laterally relative to the printing head by a distance d 1 , where d 1 =3n 2 ; and (b) printing a set of z rows of subpixels with the printing head; (6) moving and printing in a second pattern with the steps: (c) moving the workpiece laterally relative to the printing head by a distance d 2 , where d 2 =3n 3 , such that d 1 +d 2 =pz; and (d) printing a set of z rows of subpixels with the printing head; (7) repeating steps (5) and (6) multiple times in the same order; and (8) applying r colors by a non-printing method. 
     Variables include:
         n 1 , an integer greater than 0;   n 2  and n 3 , odd integers, such that n 2 +n 3 =2n 1 ;   q, an integer from 1-3; and   r, an integer, such that q+r=3.

RELATED APPLICATION

This application claims priority under 35 U.S.C. §119(e) from Provisional Application No. 61/184,091 filed Jun. 4, 2009, which is incorporated by reference in its entirety.

FIELD OF THE DISCLOSURE

This disclosure relates in general to electronic devices and processes, and more particularly, to electronic devices having electrodes and organic active regions of different colors, and processes of forming the same.

DESCRIPTION OF THE RELATED ART

An electronic device can include a liquid crystal display (“LCD”), an organic light-emitting diode (OLED) display, or the like. The manufacture of electronic devices may be performed using solution deposition techniques. One process of making electronic devices is to deposit organic layers over a substrate by printing (e.g., ink-jet printing, continuous printing, etc.). In a printing process, the liquid composition being printed includes an organic material in a solution, dispersion, emulsion, or suspension with an organic solvent, with an aqueous solvent, or with a combination of solvents. After printing, the solvent(s) is (are) evaporated and the organic material remains to form an organic layer for the electronic device.

Typically, a first color is printed and then the printing device is recalibrated and a second color is printed. In some cases, the substrate with the first printed color is moved to a second printer for printing the second color. This also requires time for setting up the printer and alignment. In many cases, three colors are printed: red, green, and blue. In this case, time must be taken to recalibrate and/or realign with each color. There is a need for improved printing processes.

SUMMARY

There is provided a process of forming a regular array of rows of subpixels on a workpiece, the subpixels having 3 different colors, and having a subpixel pitch s, and wherein q colors are formed by printing and r colors are formed by a non-printing method, said process comprising:

-   -   (1) providing a printing head having z nozzles arranged in a row         with a spacing between the nozzles of p, where z=3n₁ and p=2s,         the printhead being at a first position relative to the         workpiece;     -   (2) providing q different printing inks, one for each of the q         printed colors;     -   (3) supplying each of the printing inks to the nozzles in a         regular alternating pattern;     -   (4) printing a first set of z rows of subpixels with the         printing head;     -   (5) moving and printing in a first pattern comprising:         -   (a) moving the workpiece laterally relative to the printing             head by a distance d₁, where d₁=3n₂s;         -   (b) printing a set of z rows of subpixels with the printing             head;     -   (6) moving and printing in a second pattern comprising:         -   (c) moving the workpiece laterally relative to the printing             head by a distance d₂, where d₂=3n₃s, such that d₁+d₂=pz;             and         -   (d) printing a set of z rows of subpixels with the printing             head;     -   (7) repeating steps (5) and (6) multiple times in the same         order; and     -   (8) applying r colors by a non-printing method;         where:     -   n₁ is an integer greater than 0;     -   n₂ and n₃ are the same or different and are odd integers, such         that n₂+n₃=2n₁;     -   q is an integer from 1-3; and     -   r is an integer, such that q+r=3.

The foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as defined in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments are illustrated in the accompanying figures to improve understanding of concepts as presented herein.

FIG. 1 includes an illustration of a cross-sectional view of the workpiece and a printer.

FIG. 2 includes another illustration of a cross-sectional view of the workpiece and a different printer.

FIG. 3 includes a plan view of a workpiece for making an electronic device including a display.

FIG. 4 includes a diagram illustrating a printing method with nine nozzles.

FIG. 5 includes diagram illustrating another printing method with nine nozzles

FIG. 6 includes a diagram illustrating another printing method with nine nozzles.

FIG. 7 includes a diagram illustrating another printing method with 12 nozzles.

FIG. 8 includes a diagram illustrating another printing method with 12 nozzles.

FIG. 9 includes a diagram illustrating another printing method with 15 nozzles.

FIG. 10 includes a diagram illustrating another printing method with nine nozzles.

Skilled artisans appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the invention.

DETAILED DESCRIPTION

Many aspects and embodiments have been described above and are merely exemplary and not limiting. After reading this specification, skilled artisans appreciate that other aspects and embodiments are possible without departing from the scope of the invention.

Other features and benefits of any one or more of the embodiments will be apparent from the following detailed description, and from the claims. The detailed description first addresses Definitions and Clarification of Terms followed by the Printer, the Printing Process, the Electronic Device, and finally, Examples.

1. Definitions and Clarification of Terms

Before addressing details of embodiments described below, some terms are defined or clarified.

The term “array” is intended to mean an ordered arrangement of elements. An array may include pixels, subpixels, cells, or other structures within an ordered arrangement, usually designated by columns and rows. The array can be described in terms of an x-direction and a y-direction.

The term “blue” refers to light having a wavelength in a range of approximately 400 to 500 nm.

The term “continuous” and its variants are intended to mean substantially unbroken. In one embodiment, continuously printing is printing using a substantially unbroken stream of a liquid or a liquid composition, as opposed to a depositing technique using drops. In another embodiment, extending continuously refers to a length of a layer, member, or structure in which no significant breaks in the layer, member, or structure lie along its length.

The term “dopant” is intended to mean a material, within a layer including a host material, that changes the electronic characteristic(s) or the targeted wavelength of radiation emission, reception, or filtering of the layer compared to the electronic characteristic(s) or the wavelength of radiation emission, reception, or filtering of the layer in the absence of such material. The dopant is present in lower concentration that the host material.

The term “electronic device” is intended to mean a collection of circuits, electronic components, or any combination thereof that collectively, when properly electrically connected and supplied with the appropriate potential(s), performs a function. An electronic device may be included or be part of a system. An example of an electronic device includes a display, a sensor array, a computer system, an avionics system, an automobile, a cellular phone, other consumer or industrial electronic product, or any combination thereof.

The term “green” refers to light having a wavelength in a range of approximately 500 to 600 nm.

The term “integer” as used herein does not encompass negative integers.

The term “liquid composition” is intended to mean a liquid medium in which a material is dissolved to form a solution, a liquid medium in which a material is dispersed to form a dispersion, or a liquid medium in which a material is suspended to form a suspension or an emulsion.

The term “liquid medium” is intended to mean a liquid within a solution, dispersion, suspension, or emulsion. The term “liquid medium” is used regardless whether one or more solvents are present, and therefore, liquid medium is used as the singular or plural form (i.e., liquid media) of the term.

The term “nozzle” is intended to mean a portion of an apparatus through which a liquid composition or liquid medium can be dispensed.

The term “oriented” is intended to mean a principal direction in which a feature extends. As between different features at the same elevation or at different elevations, the features may be oriented substantially parallel, substantially perpendicular, or in another angular relationship with respect to each other.

The term “organic active layer” is intended to mean one or more organic layers, wherein at least one of the organic layers, by itself, or when in contact with a dissimilar material is capable of forming a rectifying junction. The term “organic active region” is intended to mean one or more organic region, wherein at least one of the organic regions, by itself, or when in contact with a dissimilar material is capable of forming a rectifying junction.

The term “pitch” is intended to mean a sum of a feature dimension and a space dimension between immediately adjacent features.

The term “pixel” is intended to mean the smallest complete, repeating unit of an array. The term “subpixel” is intended to mean a portion of a pixel that makes up only a part, but not all, of a pixel. A subpixel is one of the components of a pixel used in the representation of a color image. Each subpixel represents the contribution of a single color to the overall color and brightness of the pixel. A sensor array can include pixels that may or may not include subpixels.

The term “printing” is intended to mean an act of selectively depositing a layer by using a printing head or other similar structure to dispense a liquid or liquid composition onto a workpiece.

The term “printing apparatus” is intended to mean a combination of one or more materials, equipment, assembly or subassembly designed for printing a layer onto a workpiece.

The term “red” refers to light having a wavelength in a range of approximately 600 to 750 nm.

The term “resolution limit” is intended to mean the smallest feature size that can be reproducibly formed when using a particular apparatus or other equipment.

The term “workpiece” is intended to mean a substrate with one or more device layers thereon. A device layer can be inorganic or organic.

As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of features is not necessarily limited only to those features but may include other features not expressly listed or inherent to such process, method, article, or apparatus. Further, unless expressly stated to the contrary, “or” refers to an inclusive-or and not to an exclusive-or. For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).

Also, the use of “a” or “an” are employed to describe elements and components described herein. This is done merely for convenience and to give a general sense of the scope of the invention. This description should be read to include one or at least one and the singular also includes the plural unless it is obvious that it is meant otherwise.

Group numbers corresponding to columns within the Periodic Table of the elements use the “New Notation” convention as seen in the CRC Handbook of Chemistry and Physics, 81^(st) Edition (2000-2001).

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present invention, suitable methods and materials are described below. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety, unless a particular passage is cited. In case of conflict, the present specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.

To the extent not described herein, many details regarding specific materials, processing acts, and circuits are conventional and may be found in textbooks and other sources within the organic light-emitting diode display, photodetector, photovoltaic, and semiconductive member arts.

2. Printer

Before addressing particular embodiments, the printer is addressed to aid in understanding the concepts as described herein.

As shown in FIG. 1, printer 10 has a printing head 110 with six nozzles 120 attached. The spacing between the nozzles is shown as p. The printer is attached to lines (not shown) to supply the appropriate liquid composition to each nozzle. The different liquid compositions, one for each of the three colors, are supplied in a regular alternating pattern. By this is meant that one of each color is supplied before any are duplicated, and that additional colors are supplied in the same order. In this figure, the first nozzle can have color 1, the second nozzle color 2, the third nozzle color 3, the fourth nozzle color 1, the fifth nozzle color 2, and the sixth nozzle color 3. Thus, in this system, z=3n₁=6, where n₁=2.

The printing head is shown over workpiece 20. The printing head and workpiece can be moved with respect to each other. When printing, the printing head will move in the direction in and out of the plane of the paper with respect to the workpiece. The printing head will also move laterally with respect to the workpiece as shown by L. This movement is relative. In some cases, the workpiece is moved. In some cases, the printing head is moved. In some cases, both the printing head and the workpiece are moved. For simplicity, the movement will be addressed as if only the printing head moved, and as if the workpiece were stationery. It will be understood that either or both of the printing head and workpiece can be moved and it is only their movement relative to each other that is at issue.

A second printer is illustrated in FIG. 2. Printer 30 has a printing head 310, with nine nozzles 320. This printer can be used for printing three colors, R, G, and B. In this system, z=3n₁=9, where n₁=3. The liquid compositions can be supplied so that the first nozzle has R, the second nozzle has G, the third nozzle has B, the fourth nozzle has R, the fifth nozzle has G, the sixth nozzle has B, and so forth. The actual order of the colors is not important, so long as they are in a regular alternating pattern. As in FIG. 1, the printing head moves in and out of the plane of the paper to print, and can shift laterally in the direction shown by L.

In the embodiment shown in FIG. 1, the printer has six nozzles. In the embodiment shown in FIG. 2, the printer has nine nozzles. The actual number of nozzles can be greater than this and is limited only by practical manufacturing considerations. In some embodiments, the number of nozzles ranges from 9 to 24.

The printing delivery can be by any known system for depositing liquid materials. Some examples of printing techniques include, but are not limited to ink jet and continuous nozzle spray.

3. Printing Process

FIG. 3 includes a plan view of workpiece 20 for making an electronic device. The workpiece includes a substrate 200 having a regular array of subpixel openings 210. The workpiece has a first edge 201 and an opposite edge 202. Only a few subpixels are illustrated in the figure. In practice, devices may have hundreds of subpixels or more. In some embodiments, the subpixel openings are defined by a containment structure (not shown) which can be a physical containment structure, a chemical containment structure, or both. The subpixel openings 210 are in a regular array of rows, shown as 211, 212, and 213. The subpixel pitch is shown as s. In some embodiments, subpixel pitch is in the range of 1-100 microns; in some embodiments, 2-20 microns. Three subpixels together form pixel 220. In the illustrated embodiment, the subpixels 210 have a rectangular shape. Other subpixel shapes can be used, such as circular, oval, square, or polygonal. The printing direction is shown as x in the figure. Lateral movement is defined as movement in the y direction, perpendicular to the printing direction.

In the process described herein, a regular array of rows of subpixels of three colors is formed on a workpiece. Of the three colors, q colors are printed and r colors are formed by a non-printing process. The subpixels have a subpixel pitch s. The process comprises:

-   -   (1) providing a printing head having z nozzles arranged in a row         with a spacing between the nozzles of p, where z=3n₁ and p=2s,         the printhead being at a first position relative to the         workpiece;     -   (2) providing q different printing inks, one for each of the q         printed colors;     -   (3) supplying each of the printing inks to the nozzles in a         regular alternating pattern;     -   (4) printing a first set of z rows of subpixels with the         printing head;     -   (5) moving and printing in a first pattern comprising:         -   (a) moving the workpiece laterally relative to the printing             head by a distance d₁, where d₁=3n₂s;         -   (b) printing a set of z rows of subpixels with the printing             head;     -   (6) moving and printing in a second pattern comprising:         -   (c) moving the workpiece laterally relative to the printing             head by a distance d₂, where d₂=3n₃s, such that d₁+d₂=pz;             and         -   (d) printing a set of z rows of subpixels with the printing             head;     -   (7) repeating steps (5) and (6) multiple times in the same         order; and     -   (8) applying r colors by a non-printing method;         where:     -   n₁ is an integer greater than 0;     -   n₂ and n₃ are the same or different and are odd integers, such         that n₂+n₃=2n₁;     -   q is an integer from 1-3; and     -   r is an integer, such that q+r=3.

The number of colors to be formed is three. In some embodiments, the colors are red, green and blue (“R, G, B”). Of the three colors, q are formed by printing and r are formed by a non-printing process. In some embodiments, q=3 and r=0, and all three colors are printed. In some embodiments, q=2 and r=1. In this case, two of the colors are printed and the third color is applied by a non-printing method. The third color can be applied before or after printing. In some embodiments, the third color is applied after the two printed colors.

The printing head has z nozzles. When all three colors are printed, all z nozzles are present and supplied with ink. When one or more colors are applied by a non-printing method, a nozzle space is present for the non-printed color(s). The nozzle may be present and not supplied with ink, or the nozzle may be physically absent. For the purposes of the printing pattern, a nozzle space is counted as a nozzle.

The number of nozzles, z, is a multiple of the number of colors, 3. Thus, z=3n₁, where n₁ is an integer greater than 0. In some embodiments, n₁ is at least 2. In some embodiments, n₁=3-9; in some embodiment, 5-8.

The printing head starts at a first printing position over the workpiece. This first position is referred to as A1, which will be discussed in a later section. In some embodiments, the printer is positioned at one edge of the workpiece, shown as 201 in FIG. 3, and aligned to be over the first row of subpixels. The nozzles are spaced apart by a distance p, which is equal to twice the subpixel pitch, so that they are all aligned to print in the subpixel rows. Thus, they are spaced apart by a multiple of the subpixel pitch, s, and p=2s. The term “multiple of a number” means a value which is the number times an integer greater than 0.

The printer prints across the workpiece in the x-direction, as shown in FIG. 3, to print a first set of rows of subpixels. The number of rows printed is equal to the number of nozzles on the printing head=z. The number of rows of color deposited is equal to the number of nozzles supplied with color.

After completion of the printing of the first set of rows, a first printing pattern is formed in step (5). The printing head moves laterally across the workpiece to an adjacent printing position. This position is referred to as A2, which will be discussed in a later section. This movement is parallel to the plane of the workpiece and in the y-direction, which is perpendicular to the row direction. The distance moved, d₁, is also a multiple of the subpixel pitch, s, and is equal to 3n₂(s). The number n₂ is an odd integer. Thus, the lateral movement of the printing head is not a multiple of two and is not a multiple of the nozzle spacing, p, which is 2s. If the lateral movement were a multiple of the nozzle spacing, then some rows could be overprinting where a previous row was printed. A set of z rows is then printed from position A2. The printing can be in the opposite direction from the first printing or the printing head can return to the same side as for the first printing and print in the same direction. This is determined by the design of the equipment and the software. This completes the printing of the first printing pattern.

After completion of the first printing pattern, a second printing pattern is formed in step (6). The printing head to move laterally across the workpiece to an adjacent printing position. This position is referred to as A3, which will be discussed in a later section. This movement is parallel to the plane of the workpiece and in the y-direction, which is perpendicular to the row direction. The distance moved, d₂, is a multiple of the subpixel pitch, s, and is equal to 3n₃(s). The number n₃ is an odd integer. The sum of the first and second lateral movements, d₁+d₂, is equal to pz. Since p=2s and z=3n₁, the relationship between n₁, n₂, and n₃ can be derived as follows:

d ₁ +d ₂ =pz

(3n ₂ s)+(3n ₃ s)=(2s)(3n ₁)

n ₂ s+n ₃ s=2s(n ₁)

n ₂ +n ₃=2n ₁

Another set of z rows is then printed from position A3. The printing can be in the opposite direction from the second printing or the printing head can return to the same side as for the first printing and print in the same direction. This is determined by the design of the equipment and the software. This completes the printing of the second pattern.

In step (7), the steps of printing the first and second printing patterns are repeated multiple times in the same order until the desired number of subpixel rows have been printed.

In practice, the subpixel rows can be printed in any order. The movements of the printing head relative to the workpiece will be as discussed above, and the subpixel rows will be printed starting from position A1, A2, A3, etc., but not necessarily in order. The exact order of printing will be generally be determined by the most efficient way to utilize the printer.

In step (8), r colors are applied by a non-printing deposition method. When r=0, there is no step (8). Examples of non-printing methods include, but are not limited to, vapor deposition, thermal transfer, and continuous liquid deposition techniques such as spin coating, gravure coating, curtain coating, dip coating, slot-die coating, and spray coating. In these cases, where r>0, the printing must leave open spaces for the non-printed colors, which can be applied before or after the printing step. For the purposes of the printing pattern, an open space is counted as a color. When r>1, and more the one color is applied by a non-printing deposition method, the same or different non-printing method may be used for the different non-printed colors.

A summary of the different combinations of d₁ and d₂ for an exemplary, non-limiting set of different numbers of nozzles is given in Table 1. The table represents printing heads having 9-27 nozzles. It will be understood that different numbers of nozzles can also be used, as long as the number is a multiple of 3.

TABLE 1 z d₁ d₂ 9 3 15 9 9 15 3 12 3 21 9 15 15 9 21 3 15 3 27 9 21 15 15 21 9 27 3 18 3 33 9 27 15 21 21 15 27 9 33 3 21 3 39 9 33 15 27 21 21 27 15 33 9 39 3 24 3 45 9 39 15 33 21 27 27 21 33 15 39 9 45 3 27 3 51 9 45 15 39 21 33 27 27 33 21 39 15 45 9 51 3 It can be seen from the table that the case where d₁=d₂ occurs only when the number of nozzles, and hence n₁, is an odd number and n₁=n₂.

As is shown in the Examples, different printing schemes result in different numbers of unfilled subpixels at the first edge and the opposite edge of the workpiece. The choice of printing scheme will generally depend on the device size and design.

4. Electronic Device

Devices for which the printing method described herein can be used include organic electronic devices. The term “organic electronic device” or sometimes just “electronic device” is intended to mean a device including one or more organic semiconductor layers or materials. An organic electronic device includes, but is not limited to: (1) a device that converts electrical energy into radiation (e.g., a light-emitting diode, light emitting diode display, diode laser, or lighting panel), (2) a device that detects a signal using an electronic process (e.g., a photodetector, a photoconductive cell, a photoresistor, a photoswitch, a phototransistor, a phototube, an infrared (“IR”) detector, or a biosensors), (3) a device that converts radiation into electrical energy (e.g., a photovoltaic device or solar cell), (4) a device that includes one or more electronic components that include one or more organic semiconductor layers (e.g., a transistor or diode), or any combination of devices in items (1) through (4).

In such devices, an organic active layer is sandwiched between two electrical contact layers. One example of an organic electronic device structure is an OLED. The device has a first electrical contact layer, which is an anode layer, and a second electrical contact layer, which is a cathode layer. At least one of the electrical contact layers is light-transmitting so that light can pass through the electrical contact layer. A photoactive layer is between them. Additional layers may optionally be present. Adjacent to the anode may be a buffer layer. Adjacent to the buffer layer may be a hole transport layer, comprising hole transport material. Adjacent to the cathode may be an electron transport layer, comprising an electron transport material. As an option, devices may use one or more additional hole injection or hole transport layers next to the anode and/or one or more additional electron injection or electron transport layers next to the cathode.

It is well known to use organic electroluminescent compounds as the active component in such devices to provide the necessary colors. The printing method described herein is suitable for the printing of liquid compositions containing electroluminescent materials having different colors. Such materials include, but are not limited to, small molecule organic fluorescent compounds, fluorescent and phosphorescent metal complexes, conjugated polymers, and mixtures thereof. Examples of fluorescent compounds include, but are not limited to, chrysenes, pyrenes, perylenes, rubrenes, coumarins, anthracenes, thiadiazoles, derivatives thereof, and mixtures thereof. Examples of metal complexes include, but are not limited to, metal chelated oxinoid compounds, such as tris(8-hydroxyquinolato)aluminum (Alq3); cyclometalated iridium and platinum electroluminescent compounds, such as complexes of iridium with phenylpyridine, phenylquinoline, or phenylpyrimidine ligands as disclosed in Petrov et al., U.S. Pat. No. 6,670,645 and Published PCT Applications WO 03/063555 and WO 2004/016710, and organometallic complexes described in, for example, Published PCT Applications WO 03/008424, WO 03/091688, and WO 03/040257, and mixtures thereof. In some cases the small molecule fluorescent or organometallic materials are deposited as a dopant with a host material to improve processing and/or electronic properties. Examples of conjugated polymers include, but are not limited to poly(phenylenevinylenes), polyfluorenes, poly(spirobifluorenes), polythiophenes, poly(p-phenylenes), copolymers thereof, and mixtures thereof.

To form the printing inks, the above materials are dissolved or dispersed in a suitable liquid composition. A suitable solvent for a particular compound or related class of compounds can be readily determined by one skilled in the art. For some applications, it is desirable that the compounds be dissolved in non-aqueous solvents. Such non-aqueous solvents can be relatively polar, such as C₁ to C₂₀ alcohols, ethers, and acid esters, or can be relatively non-polar such as C₁ to C₁₂ alkanes or aromatics such as toluene, xylenes, trifluorotoluene and the like. Other suitable liquids for use in making the liquid composition, either as a solution or dispersion as described herein, comprising the new compounds, includes, but not limited to, chlorinated hydrocarbons (such as methylene chloride, chloroform, chlorobenzene), aromatic hydrocarbons (such as substituted and non-substituted toluenes and xylenes), including triflurotoluene), polar solvents (such as tetrahydrofuran (THP), N-methylpyrrolidone) esters (such as ethylacetate) alcohols (isopropanol), keytones (cyclopentatone) and mixtures thereof. Suitable solvents for photoactive materials have been described in, for example, published PCT application WO 2007/145979.

EXAMPLES

The concepts described herein will be further described in the following examples and associated figures, which do not limit the scope of the invention described in the claims.

Example 1

Example 1 is illustrated in FIG. 4. The three colors are shown as red, green and blue, and all of the colors are printed. There are 9 nozzles on the printing head, and the spacing between nozzles is 2 units of subpixel pitch. Thus, in this example, q=3, r=0, z=9 and n₁=3.

The colors are arranged as shown under the column labeled “Printer.” The printing head is positioned at the first edge with the first nozzle, having red, over subpixel row 1. This is the first printing position shown as A1. The position A1 is defined as the subpixel row over which the first nozzle is placed. The printer prints across the workpiece in the row direction to form a row of red color in subpixel row 1, a row of green color in subpixel row 3, a row of blue color in subpixel row 5, a row of red color in subpixel row 7, a row of green color in subpixel row 9, a row of blue color in subpixel row 11, a row of red color in subpixel row 13, a row of green color in subpixel row 15, and a row of blue color in subpixel row 17. This is shown in the column labeled Print #1. Only one subpixel is shown for each color for purposes of clarity, but each represents an entire row of subpixels.

The next step is to form the first printing pattern, step (5). The printer shifts laterally by a distance d₁ which is 3n₂ subpixel units. In this case n₂=1 and d₁=3s. This is position A2 for the printer. The printer then prints another set of rows: a row of red color in subpixel row 4, a row of green color in subpixel row 6, a row of blue color in subpixel row 8, a row of red color in subpixel row 10, a row of green color in subpixel row 12, a row of blue color in subpixel row 14, a row of red color in subpixel row 16, a row of green color in subpixel row 18, and a row of blue color in subpixel row 20, as shown in the column labeled Print #2. Print #2 is shown shifted to the right of Print #1 for purposes of clarity. Both Print #1 and Print #2, as well as all the other Print numbers, represent full rows of printed subpixels across the workpiece. This completes the first printing pattern.

The next step is to form the second printing pattern, step (6). The printer shifts laterally by d₂ subpixel units, where d₂ which is 3n₃ subpixel units. Since n₂+n₃=2n₁, then n₃ is equal to 2n₁−n₂=2·3−1=5. Thus, d₂=3n₃s=15s. The distance d₂ could also be calculated as equal to pz−d₁, where d₁=3s. As stated above, p=2s and z=9. Thus d₂=2s·9−3s=15s. This is position A3 for the printer. The printer then prints a third set of rows: a row of red color in subpixel row 19, a row of green color in subpixel row 21, a row of blue color in subpixel row 23, a row of red color in subpixel row 25, a row of green color in subpixel row 27, a row of blue color in subpixel row 29, a row of red color in subpixel row 31, a row of green color in subpixel row 33, and a row of blue color in subpixel row 35, as shown in the column labeled Print #3. This completes the second printing pattern.

The next step, step (7), is to repeat steps (5) and (6) in order. To repeat step (5), the printer shifts laterally by a distance d₁=3s. This is position A4 for the printer. The printer then prints another set of rows: a row of red color in subpixel row 22, a row of green color in subpixel row 24, a row of blue color in subpixel row 26, a row of red color in subpixel row 28, a row of green color in subpixel row 30, a row of blue color in subpixel row 32, a row of red color in subpixel row 34, a row of green color in subpixel row 36, and a row of blue color in subpixel row 38, as shown in the column labeled Print #4.

To repeat step (6), the printer shifts laterally by a distance d₂=15s. This is position A5 for the printer. The printer then prints another set of rows: a row of red color in subpixel row 37, a row of green color in subpixel row 39, a row of blue color in subpixel row 41, a row of red color in subpixel row 43, a row of green color in subpixel row 45, a row of blue color in subpixel row 47, a row of red color in subpixel row 49, a row of green color in subpixel row 51, and a row of blue color in subpixel row 53, as shown in the column labeled Print #5.

At this point, the printer has printed five sets of nine rows of subpixels, which is equal to 45 subpixel rows. At this time the printing has reached the opposite edge of the workpiece and printing is complete. In practice, most devices will require many more rows, up to hundreds of subpixel rows and more, and these rows will be printed in an analogous manner. The 45 subpixel rows in the figure are shown only as an illustration.

The printed outcome is shown in the column labeled “Pattern”. It can be seen that subpixel row 2 at the first edge and subpixel rows 40, 42, 44, 46, 48, 50, and 52 at the opposite edge have no color. Complete sets of three subpixels are present from subpixel row 3 to subpixel row 38. Although red, blue, and green are exemplified in this figure, other colors could be used.

Example 2

Example 2 is illustrated in FIG. 5. The three colors are shown as red, green and blue, and all of the colors are printed. There are 9 nozzles on the printing head, and the spacing between nozzles is 2 units of subpixel pitch. Thus, in this example, q=3, r=0, z=9 and n₁=3.

The colors are arranged as shown under the column labeled “Printer.” The printing head is positioned at the first edge with the first nozzle, having red, over subpixel row 1. This is the first printing position shown as A1. The position A1 is defined as the subpixel row over which the first nozzle is placed. The printer prints across the workpiece in the row direction to form a row of red color in subpixel row 1, a row of green color in subpixel row 3, a row of blue color in subpixel row 5, a row of red color in subpixel row 7, a row of green color in subpixel row 9, a row of blue color in subpixel row 11, a row of red color in subpixel row 13, a row of green color in subpixel row 15, and a row of blue color in subpixel row 17. This is shown in the column labeled Print #1. Only one subpixel is shown for each color for purposes of clarity, but each represents an entire row of subpixels.

The next step is to form the first printing pattern. The printer shifts laterally by a distance d₁ which is 3n₂ subpixel units. In this case n₂=5 and d₁=15s. This is position A2 for the printer. The printer then prints another set of rows: a row of red color in subpixel rows 16, a row of green color in subpixel row 18, a row of blue color in subpixel row 20, a row of red color in subpixel rows 22, a row of green color in subpixel row 24, a row of blue color in subpixel row 26, a row of red color in subpixel rows 28, a row of green color in subpixel row 30, and a row of blue color in subpixel row 32, as shown in the column labeled Print #2. Print #2 is shown shifted to the right of Print #1 for purposes of clarity. Both Print #1 and Print #2, as well as all the other Print numbers, represent full rows of printed subpixels across the workpiece. This completes the first printing pattern.

The next step is to form the second printing pattern. The printer then shifts laterally by d₂ subpixel units, where d₂=pz−d₁=3s. This is position A3 for the printer. The printer then prints a third set of rows: a row of red color in subpixel row 19, a row of green color in subpixel row 21, a row of blue color in subpixel row 23, a row of red color in subpixel row 25, a row of green color in subpixel row 27, a row of blue color in subpixel row 29, a row of red color in subpixel row 31, a row of green color in subpixel row 33, and a row of blue color in subpixel row 35, as shown in the column labeled Print #3. This completes the second printing pattern.

Next, the first and second printing patterns are repeated in order. The printer shifts laterally by a distance d₁=15s. This is position A4 for the printer. The printer then prints another set of rows: a row of red color in subpixel row 34, a row of green color in subpixel row 36, a row of blue color in subpixel row 38, a row of red color in subpixel row 40, a row of green color in subpixel row 42, a row of blue color in subpixel row 44, a row of red color in subpixel row 46, a row of green color in subpixel row 48, and a row of blue color in subpixel row 50, as shown in the column labeled Print #4.

The printer then shifts laterally by a distance d₂=3s. This is position A5 for the printer. The printer then prints another set of rows: a row of red color in subpixel row 37, a row of green color in subpixel row 39, a row of blue color in subpixel row 41, a row of red color in subpixel row 43, a row of green color in subpixel row 45, a row of blue color in subpixel row 47, a row of red color in subpixel row 49, a row of green color in subpixel row 51, and a row of blue color in subpixel row 53, as shown in the column labeled Print #5.

At this point, the printer has printed five sets of nine rows of subpixels, which is equal to 45 subpixel rows. As discussed above, most devices will require many more rows, up to hundreds of subpixel rows and more, and the 45 subpixel rows in the figure are shown only as an illustration.

The printed outcome is shown in the column labeled “Pattern”. It can be seen that subpixel row 2, 4, 6, 8, 10, 12 and 14 at the first edge and subpixel row 52 at the opposite edge have no color. Complete sets of three subpixels are present from subpixel row 15 to subpixel row 50. Although red, blue, and green are exemplified in this figure, other colors could be used.

Example 3

Example 3 is illustrated in FIG. 6. The three colors are shown as red, green, and blue, and all of the colors are printed. There are 9 nozzles on the printing head and the spacing between nozzles is 2 units of subpixel pitch. As in Example 1, q=3, r=0, z=9 and n₁=3.

The colors are arranged as shown in the “Printer” column, with the printing head positioned at position A1. The first printed row is the same as in Example 1: a row of red in subpixel row 1, a row of green in subpixel row 3, a row of blue in subpixel row 5, a row of red in subpixel row 7, a row of green in subpixel row 9, a row of blue in subpixel row 11, a row of red in subpixel row 13, a row of green in subpixel row 15, and a row of blue in subpixel row 17. This is shown in the column labeled Print #1. As in Example 1, only one subpixel is shown for each color for purposed of clarity, but each represents an entire row of subpixels.

The next step is to form the first printing pattern. The printer shifts laterally by a distance d₁ which is 3n₂ subpixel units. In this case n₂=3 and d₁=9s. This is position A2 for the printer. The printer then prints another set of rows: red in subpixel rows 10, 16, and 22; green in subpixel rows 12, 18, and 24; and blue in subpixel rows 14, 20, and 26. This is shown in the Print #2 column. Print #2 is shown shifted to the right of Print #1 for purposes of clarity. Both Print #1 and Print #2, as well as all the other Print numbers, represent full rows of printed subpixels across the workpiece. This completes the first printed pattern.

The printer then shifts laterally by d₂ subpixel units. d₂ is equal to pz−d₁, where p=2s, z=9, and d₁=9s. Thus, in this illustration, d₂=2s·9−9s=9s, so that d₁=d₂. This is position A3 for the printer, for Print #3. The printer is then shifted d₁=9 subpixel units for Print #4, and shifted d₂=9 subpixel units for Print #5. In this case, all the lateral shifts are the same distance of 9s. It will be the case that d₁=d₂ when n₁=n₂=n₃ and the distance of the lateral shift is equal to the total number of nozzles time the subpixel pitch. This case will only occur for odd numbers of nozzles since n₂ must be an odd number.

At this point, the printer has printed five sets of nine rows of subpixels, which is a total of 45 subpixel rows. As discussed above, most devices will require many more rows, up to hundreds of subpixel rows and more, and the 45 subpixel rows in the figure are shown only as an illustration. The printed outcome is shown in the column labeled “Pattern”. It can be seen that color is missing for subpixel rows 2, 4, 6, and 8 at the first edge and subpixel rows 46, 48, 50, and 52 at the opposite edge. Complete sets of the three colors, and thus the usable device area, can be found from subpixel row 9 to subpixel row 44. Although red, blue, and green are exemplified in this figure, other colors could be used.

Example 4

Example 4 is illustrated in FIG. 7. The three colors are shown as red, green, and blue, and all the colors are printed. There are 12 nozzles on the printing head, so that q=3, r=0, z=12 and n₁=4.

The colors are arranged as shown in the “Printer” column. The first printed row is shown in the column labeled Print #1: a row of red in subpixel row 1, a row of green in subpixel row 3, a row of blue in subpixel row 5, a row of red in subpixel row 7, a row of green in subpixel row 9, a row of blue in subpixel row 11, a row of red in subpixel row 13, a row of green in subpixel row 15, a row of blue in subpixel row 17, a row of red in subpixel row 19, a row of green in subpixel row 21, and a row of blue in subpixel row 23. As in Example 1, only one subpixel is shown for each color for purposes of clarity, but each represents an entire row of subpixels.

For the first printing pattern, the printer shifts laterally by a distance d₁ which is 3n₂ subpixel units. In this case n₂=1 and d₁=3s. This is position A2 for the printer. The printer then prints a second set of rows: red in subpixel rows 4, 10, 16, and 22; green in subpixel rows 6, 12, 18, and 24; and blue in subpixel rows 8, 14, 20, and 26. This is shown in the Print #2 column. Print #2 is shown shifted to the right of Print #1 for purposes of clarity. Both Print #1 and Print #2, as well as all the other Print numbers, represent full rows of printed subpixels across the workpiece. This completes the first printing pattern.

The printer then shifts laterally by d₂ subpixel units, for the second printing pattern. d₂ is equal to pz−d₁, where p=2s, z=12, and d₁=3s. Thus, in this illustration, d₂=2s·12−3s=21s. This is position A3 for the printer, for Print #3. The printer then prints a third set of rows: red in subpixel rows 25, 31, 37, and 43; green in subpixel rows 27, 33, 39, and 45; and blue in subpixel rows 29, 35, 41, and 47. This is shown in the Print #3 column.

The first printing pattern is then repeated and the printer shifts laterally by d₁=3s to position A4. The printer then prints a third set of rows: red in subpixel rows 28, 34, 40, and 46; green in subpixel rows 30, 36, 42, and 48; and blue in subpixel rows 32, 38, 44, and 50. This is shown in the Print #4 column.

At this point, the printer has printed four sets of 12 rows of subpixels, which is a total of 48 subpixel rows. As discussed above, most devices will require many more rows, up to hundreds of subpixel rows and more, and the 48 subpixel rows in the figure are shown only as an illustration.

It is to be noted that in this example, the process was stopped with a repeat of the first printing pattern without a repeat of the second printing pattern. While the printing patterns are repeated in order, the process can be completed with either the first or second printing pattern, step (5) or (6). The choice of which printing to end with will generally depend on the device size and design.

The printed outcome is shown in the column labeled “Pattern”. It can be seen that colors are missing for subpixel rows 2 and 49. Complete sets of the three colors, and thus the usable device area, can be found from subpixel row 3 to subpixel row 47. Although red, blue, and green are exemplified in this figure, other colors could be used.

Example 5

Example 5 is illustrated in FIG. 8. The three colors are shown as red, green, and blue, and all of the colors are printed. There are 12 nozzles on the printing head, so that q=3, r=0, z=12 and n₁=4.

The colors are arranged as shown in the “Printer” column. The first printed row is shown in the column labeled Print #1: a row of red in subpixel row 1, a row of green in subpixel row 3, a row of blue in subpixel row 5, a row of red in subpixel row 7, a row of green in subpixel row 9, a row of blue in subpixel row 11, a row of red in subpixel row 13, a row of green in subpixel row 15, a row of blue in subpixel row 17, a row of red in subpixel row 19, a row of green in subpixel row 21, and a row of blue in subpixel row 23. As in Example 1, only one subpixel is shown for each color for purposes of clarity, but each represents an entire row of subpixels.

For the first printing pattern, the printer shifts laterally by a distance d₁ which is 3n₂ subpixel units. In this case n₂=3 and d₁=9s. This is position A2 for the printer. The printer then prints a second set of rows: red in subpixel rows 10, 16, 22, and 28; green in subpixel rows 12, 18, 24, and 30; and blue in subpixel rows 14, 20, 26, and 32. This is shown in the Print #2 column. Print #2 is shown shifted to the right of Print #1 for purposes of clarity. Both Print #1 and Print #2, as well as all the other Print numbers, represent full rows of printed subpixels across the workpiece. This completes the first printing pattern.

For the second printing pattern, the printer shifts laterally by d₂ subpixel units. d₂ is equal to pz−d₁, where p=2s, z=12, and d₁=9s. Thus, in this illustration, d₂=2s·12−9s=15s. This is position A3 for the printer, for Print #3. The printer then prints a third set of rows: red in subpixel rows 25, 31, 37, and 43; green in subpixel rows 27, 33, 39, and 45; and blue in subpixel rows 29, 35, 41, and 47. This is shown in the Print #3 column.

The printer then repeats the first printing pattern by shifting laterally by d₁=9s to position A4. The printer then prints a third set of rows: red in subpixel rows 34, 40, 46, and 52; green in subpixel rows 36, 42, 48, and 54; and blue in subpixel rows 38, 44, 50, and 56. This is shown in the Print #4 column.

At this point, the printer has printed four sets of 12 rows of subpixels, which is a total of 48 subpixel rows. As discussed above, most devices will require many more rows, up to hundreds of subpixel rows and more, and the 48 subpixel rows in the figure are shown only as an illustration.

The printed outcome is shown in the column labeled “Pattern”. It can be seen that colors are missing for subpixel rows 2, 4, 6, and 8 at the first edge and 49, 51, 53, and 55 at the opposite edge. Complete sets of the three colors, and thus the usable device area, can be found from subpixel row 9 to subpixel row 47. Although red, blue, and green are exemplified in this figure, other colors could be used.

Example 6

Example 6 is illustrated in FIG. 9. The three colors are shown as red, green, and blue, and all are printed. There are 15 nozzles on the printing head, so that q=3, r=0, z=15 and n₁=5.

The colors are arranged as shown in the “Printer” column. The first printed row is shown in the column labeled Print #1: a row of red in subpixel row 1, a row of green in subpixel row 3, a row of blue in subpixel row 5, a row of red in subpixel row 7, a row of green in subpixel row 9, a row of blue in subpixel row 11, a row of red in subpixel row 13, a row of green in subpixel row 15, a row of blue in subpixel row 17, a row of red in subpixel row 19, a row of green in subpixel row 21, a row of blue in subpixel row 23, a row of red in subpixel row 25, a row of green in subpixel row 27, and a row of blue in subpixel row 29. As in Example 1, only one subpixel is shown for each color for purposes of clarity, but each represents an entire row of subpixels.

For the first printing pattern, the printer shifts laterally by a distance d₁ which is 3n₂ subpixel units. In this case n₂=3 and d₁=9s. This is position A2 for the printer. The printer then prints a second set of rows: red in subpixel rows 10, 16, 22, 28, and 34; green in subpixel rows 12, 18, 24, 30, and 36; and blue in subpixel rows 14, 20, 26, 32, and 38. This is shown in the Print #2 column. Print #2 is shown shifted to the right of Print #1 for purposes of clarity. Both Print #1 and Print #2, as well as all the other Print numbers, represent full rows of printed subpixels across the workpiece. This completes the first printing pattern.

For the second printing pattern, the printer shifts laterally by d₂ subpixel units. d₂ is equal to pz−d₁, where p=2s, z=15, and d₁=9s. Thus, in this illustration, d₂=2s·15−9s=21s. This is position A3 for the printer, for Print #3. The printer then prints a third set of rows: red in subpixel rows 31, 37, 43, 49, and 55; green in subpixel rows 33, 39, 45, 51, and 57; and blue in subpixel rows 35, 41, 47, 53, and 59. This is shown in the Print #3 column. This completes the second printing pattern.

The printer then repeats the first printing pattern by shifting laterally by d₁=9s to position A4. The printer then prints a fourth set of rows: red in subpixel rows 40, 46, 52, 58, and 64; green in subpixel rows 42, 48, 54, 60, and 66; and blue in subpixel rows 44, 50, 56, 62, and 68. This is shown in the Print #4 column.

The printer then repeats the second printing pattern by shifting laterally by d₂=21s to position A5. The printer then prints a fifth set of rows: red in subpixel rows 61, 67, 73, 79, and 85; green in subpixel rows 63, 69, 75, 81, and 87; and blue in subpixel rows 65, 71, 77, 83, and 89.

The printer then repeats the first printing pattern by shifting laterally d₁=9s to position A6 and printing a sixth set of rows: red in subpixel rows 70, 76, 82, 88, and 94; green in subpixel rows 72, 78, 84, 90, and 96; and blue in subpixel rows 74, 80, 86, 92, and 98.

At this point, the printer has printed six sets of 15 rows of subpixels, which is a total of 90 subpixel rows. As discussed above, most devices will require many more rows, up to hundreds of subpixel rows and more, and the 90 subpixel rows in the figure are shown only as an illustration.

The printed outcome is shown in the column labeled “Pattern”. It can be seen that colors are missing for subpixel rows 2, 4, 6, and 8 at the first edge, and subpixel rows 91, 93, 95, and 97 at the opposite edge. Complete sets of the three colors, and thus the usable device area, can be found from subpixel row 9 to subpixel row 89. Although red, blue, and green are exemplified in this figure, other colors could be used.

There are two other embodiments (not shown) for a printer having three printed colors and 15 nozzles on the printing head, so that q=3, r=0, z=15 and n₁=5. In one embodiment, d₁=3 and d₂=27. In another embodiment, d₁=d₂=15.

Example 7

Example 7 is illustrated in FIG. 10. In this example, there is one color that is applied by a non-printing method.

There are 2 colors, M1 and M2, and an open space for a third color to be deposited at a different time, shown as “blank” in the figure. This is counted as 3 colors. There are three nozzles printing M1, three nozzles printing M2, and three nozzles that are not printing. The non-printing nozzles may or may not be physically present on the printing head. If the non-printing nozzles are not present, there is a space for them and the space is counted as a nozzle for the purposed of the printing pattern. Thus, this is counted as a total of nine nozzles. The different liquid compositions, one for each color and the lack of one for the open space, are supplied in a regular alternating pattern. The spacing between nozzles (printing nozzles and non-printing nozzles) is two units of subpixel pitch. Thus, in this example: q=2, r=1, z=9 and n₁=3.

The colors are arranged as shown in the “Printer” column, where “blank” indicates a non-printing nozzle. The printing head is positioned at the first edge with the first nozzle, having M1, over subpixel row 1. This is the first printing position shown as A1. The printer prints across the workpiece in the row direction to form a row of M1 color in subpixel row 1, a row of M2 color in subpixel row 3, no color in subpixel row 5, a row of M1 color in subpixel row 7, a row of M2 color in subpixel row 9, no color in subpixel row 11, a row of M1 color in subpixel row 13, a row of M2 color in subpixel row 15, and no color in subpixel row 17. This is shown in the column labeled Print #1. Only one subpixel is shown for each color for purposes of clarity, but each represents an entire row of subpixels.

The next step is to form the first printing pattern. The printer shifts laterally by a distance d₁ which is 3n₂ subpixel units. In this case n₂=1 and d₁=3s. This is position A2 for the printer. The printer then prints another set of rows: a row of M1 color in subpixel row 4, a row of M2 color in subpixel row 6, no color in subpixel row 8, a row of M1 color in subpixel row 10, a row of M2 color in subpixel row 12, no color in subpixel row 14, a row of M1 color in subpixel row 16, a row of M2 color in subpixel row 18, and no color in subpixel row 20, as shown in the column labeled Print #2. Print #2 is shown shifted to the right of Print #1 for purposes of clarity. Both Print #1 and Print #2, as well as all the other Print numbers, represent full rows of printed subpixels across the workpiece. This completes the first printing pattern.

The next step is to form the second printing pattern. The printer shifts laterally by d₂ subpixel units. d₂ is equal to pz−d₁, where p=2s, z=9, and d₁=3s. Thus, in this illustration, d₂=2s·9−3s=15s. This is position A3 for the printer. The printer then prints a third set of rows: a row of M1 color in subpixel row 19, a row of M2 color in subpixel row 21, no color in subpixel row 23, a row of M1 color in subpixel row 25, a row of M2 color in subpixel row 27, no color in subpixel row 29, a row of M1 color in subpixel row 31, a row of M2 color in subpixel row 33, and no color in subpixel row 35, as shown in the column labeled Print #3. This completes the second printing pattern.

The next step is to repeat the first printing pattern. The printer shifts laterally by a distance d₁=3s. This is position A4 for the printer. The printer then prints another set of rows: a row of M1 color in subpixel row 22, a row of M2 color in subpixel row 24, no color in subpixel row 26, a row of M1 color in subpixel row 28, a row of M2 color in subpixel row 30, no color in subpixel row 32, a row of M1 color in subpixel row 34, a row of M2 color in subpixel row 36, and no color in subpixel row 38, as shown in the column labeled Print #4.

The next step is to repeat the second printing pattern. The printer shifts laterally by a distance d₂=15s. This is position A5 for the printer. The printer then prints another set of rows: a row of M1 color in subpixel row 37, a row of M2 color in subpixel row 39, no color in subpixel row 41, a row of M1 color in subpixel row 43, a row of M2 color in subpixel row 45, no color in subpixel row 47, a row of M1 color in subpixel row 49, a row of M2 color in subpixel row 51, and no color in subpixel row 53, as shown in the column labeled Print #5.

At this point, the printer has printed five sets of nine rows of subpixels, which is equal to 45 subpixel rows. As discussed above, most devices will require many more rows, up to hundreds of subpixel rows and more, and the 45 subpixel rows in the figure are shown only as an illustration.

The printed outcome is shown in the column labeled “Pattern”. It can be seen that there are open subpixels that are available for a third color in the non-printing rows: subpixel rows 2, 5, 8, 11, etc. Complete sets of the two colors plus blank space for the third color, and thus the usable device area, can be found from subpixel row 1 to subpixel row 39.

The next step in the process is to apply the third color, M3, by a non-printing process. In some embodiments, the non-printing process is vapor deposition. In some embodiments, M1 and M2 are red and green, respectively, and M3 is blue.

Note that not all of the activities described above in the general description or the examples in the figures are required, that a portion of a specific activity may not be required, and that one or more further activities may be performed in addition to those described. Still further, the order in which activities are listed are not necessarily the order in which they are performed.

In the foregoing specification, the concepts have been described with reference to specific embodiments. However, one of ordinary skill in the art appreciates that various modifications and changes can be made without departing from the scope of the invention as set forth in the claims below. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of invention.

Benefits, other advantages, and solutions to problems have been described above with regard to specific embodiments. However, the benefits, advantages, solutions to problems, and any feature(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential feature of any or all the claims.

It is to be appreciated that certain features are, for clarity, described herein in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features that are, for brevity, described in the context of a single embodiment, may also be provided separately or in any subcombination. The use of numerical values in the various ranges specified herein is stated as approximations as though the minimum and maximum values within the stated ranges were both being preceded by the word “about.” In this manner slight variations above and below the stated ranges can be used to achieve substantially the same results as values within the ranges. Also, the disclosure of these ranges is intended as a continuous range including every value between the minimum and maximum average values including fractional values that can result when some of components of one value are mixed with those of different value. Moreover, when broader and narrower ranges are disclosed, it is within the contemplation of this invention to match a minimum value from one range with a maximum value from another range and vice versa. 

What is claimed is:
 1. A process of forming a regular array of rows of subpixels on a workpiece, the subpixels having 3 different colors, and having a subpixel pitch s, and wherein q colors are formed by printing and r colors are formed by a non-printing method, said process comprising: (1) providing a printing head having z nozzles arranged in a row with a spacing between the nozzles of p, where z=3n₁ and p=2s, the printhead being at a first position relative to the workpiece; (2) providing q different printing inks, one for each of the q printed colors; (3) supplying each of the printing inks to the nozzles in a regular alternating pattern; (4) printing a first set of z rows of subpixels with the printing head; (5) moving and printing in a first pattern comprising: (a) moving the workpiece laterally relative to the printing head by a distance d₁, where d₁=3n₂s; (b) printing a set of z rows of subpixels with the printing head; (6) moving and printing in a second pattern comprising: (c) moving the workpiece laterally relative to the printing head by a distance d₂, where d₂=3n₃s, such that d₁+d₂=pz; and (d) printing a set of z rows of subpixels with the printing head; (7) repeating steps (5) and (6) multiple times in the same order; and (8) applying r colors by a non-printing method; where: n₁ is an integer greater than 0; n₂ and n₃ are the same or different and are odd integers, such that n₂+n₃=2n₁; q is an integer from 1-3; and r is an integer, such that q+r=3.
 2. The process of claim 1, wherein q=3.
 3. The process of claim 1, wherein n₁ is at least
 2. 4. The process of claim 1, wherein n₁=3-9.
 5. The process of claim 1, wherein n₁ is odd and n₁=n₂=n₃.
 6. The process of claim 1, wherein each printing ink comprises an electroluminescent material and a liquid medium.
 7. The process of claim 1, wherein r is at least one and the non-printing method is selected from the group consisting of vapor deposition, thermal transfer, spin coating, gravure coating, curtain coating, dip coating, slot-die coating, and spray coating. 